Disassembly and Assembly

Disassembly

CAUTION:
^ When installing rocker arms, camshaft and oil seal, lubricate contacting surfaces with new engine oil.
^ When tightening cylinder head bolts, camshaft sprocket bolts and camshaft bracket bolts, lubricate bolt threads and seat surfaces with new engine oil.

^ If a hydraulic lash adjuster is kept on its side, there is a risk of air entering it. When hydraulic lash adjusters are removed, stand them straight up or soak them in new engine oil.
^ Do not disassemble hydraulic lash adjusters.
^ Attach tags to lash adjusters so as not to mix them up.

1. Remove rocker arms, shims, rocker arm guides and hydraulic lash adjusters from cylinder head.

CAUTION: Keep parts in order so they can be installed in their original positions during assembly.

2. Remove exhaust manifold cover.

3. Remove EGR tube.

4. Remove exhaust manifold as shown.

5. Remove EGR volume control valve assembly.

6. Remove water outlet.

7. Remove intake manifold with intake manifold collector as shown.

8. Remove valve components with Tool. Install camshaft temporarily.

9. Remove valve oil seal with a suitable tool.

Inspection
CYLINDER HEAD DISTORTION
^ Clean mating surface of cylinder head.
^ Use a reliable straightedge and feeler gauge to check the flatness of cylinder head mating surface.

^ Check along six positions shown in figure.
Head surface flatness:
Standard: Less than 0.03 mm (0.0012 inch)
Limit: 0.1 mm (0.004 inch)

If beyond the specified limit, replace or resurface it.
Resurfacing limit:
The limit for cylinder head resurfacing is determined by the amount of cylinder block resurfacing.
Amount of cylinder head resurfacing is "A".
Amount of cylinder block resurfacing is "B".
The maximum limit is as follows: A + B = 0.2 mm (0.008 inch)
After resurfacing cylinder head, check that camshaft rotates freely by hand. If resistance is felt, cylinder head must be replaced.
Nominal cylinder head height: 136.9 - 137.1 mm (5.390 - 5.398 inch)

CAMSHAFT VISUAL CHECK
Check camshaft for scratches, seizure and wear.

CAMSHAFT RUNOUT

1. Measure camshaft runout at the center journal.
Runout (Total indicator reading):
Standard Less than 0.02 mm (0.0008 inch)
Limit 0.1 mm (0.004 inch)
2. If it exceeds the limit, replace camshaft.

CAMSHAFT CAM HEIGHT

1. Measure camshaft cam height.
Standard cam height:
Intake 37.550 - 37.740 mm (1.4783 - 1.4858 inch)
Exhaust 37.920 - 38.110 mm (1.4929 - 1.5004 inch)
Cam height wear limit:
Intake & Exhaust 0.2 mm (0.008 inch)
2. If wear is beyond the limit, replace camshaft.

CAMSHAFT JOURNAL CLEARANCE
1. Install camshaft bracket and tighten bolts. Refer to "Installation", under Timing Components; Timing Chain; Service and Repair.

2. Measure inner diameter of camshaft bearing.
Standard inner diameter: 28.000 - 28.021 mm (1.1024 - 1.1032 inch)

3. Measure outer diameter of camshaft journal.
Standard outer diameter: 27.935 - 27.955 mm (1.0998 - 1.1006 inch)
4. Calculate camshaft journal clearance.
Camshaft journal clearance = standard inner diameter - standard outer diameter:
Standard 0.030 - 0.071 mm (0.0012 - 0.0028 inch)
Limit 0.15 mm (0.0059 inch)
5. If clearance exceeds the limit, replace camshaft and remeasure camshaft journal clearance.
^ If clearance still exceeds the limit after replacing camshaft, replace cylinder head.

CAMSHAFT END PLAY
1. Install camshaft in cylinder head. Refer to "Installation", under Timing Components; Timing Chain; Service and Repair.

2. Measure camshaft end play.
Camshaft end play:
Standard 0.055 - 0.139 mm (0.0022 - 0.0055 inch)
Limit 0.20 mm (0.0079 inch)
3. If end play exceeds the limit, replace camshaft and remeasure camshaft end play.
^ If end play still exceeds the limit after replacing camshaft, replace cylinder head.

CAMSHAFT SPROCKET RUNOUT
1. Install sprocket on camshaft.

2. Measure camshaft sprocket runout.
Runout (Total indicator reading): Limit 0.25 mm (0.0098 inch)
3. If it exceeds the limit, replace camshaft sprocket.

VALVE GUIDE CLEARANCE

1. Measure valve deflection as shown in illustration. (Valve and valve guide mostly wear in this direction.)
Valve deflection limit (Dial gauge reading):
Intake & Exhaust 0.2 mm (0.008 inch)

2. If it exceeds the limit, check valve to valve guide clearance.
a. Measure valve stem diameter and valve guide inner diameter.
b. Calculate valve to valve guide clearance.
Valve to valve guide clearance = valve guide inner diameter - valve stem diameter:
Standard
Intake 0.020 - 0.053 mm (0.0008 - 0.0021 inch)
Exhaust 0.040 - 0.073 mm (0.0016 - 0.0029 inch)
Limit
Intake 0.08 mm (0.0031 inch)
Exhaust 0.1 mm (0.004 inch)
c. If it exceeds the limit, replace valve and remeasure clearance. If clearance still exceeds the limit after replacing valve, replace valve guide.

VALVE GUIDE REPLACEMENT

1. To remove valve guide, heat cylinder head to 110 to 130°C (230 to 266°F).

2. Drive out valve guide with a press (under a 20 kN 12 ton, 2.2 US ton, 2.0 Imp ton] pressure) or hammer and suitable tool.

3. Ream cylinder head valve guide hole.
Valve guide hole diameter (for service parts):
Intake & Exhaust 10.175 - 10.196 mm (0.4006 - 0.4014 inch)

4. Heat cylinder head to 110 to 130°C (230 to 266°F) and press service valve guide into cylinder head.
Projection "L": 14.0 - 14.2 mm (0.551 - 0.559 inch)

5. Ream valve guide.
Finished size:
Intake & Exhaust 6.000 - 6.018 mm (0.2362 - 0.2369 inch)

VALVE SEATS

Check valve seats for pitting at contact surface. Resurface or replace if excessively worn.
^ Before repairing valve seats, check valve and valve guide for wear. If they are worn, replace them. Then correct valve seat.
^ Use both hands to cut uniformly.

REPLACING VALVE SEAT FOR SERVICE PARTS

1. Bore out old seat until it collapses. Set machine depth stop so that boring cannot contact bottom face of seat recess in cylinder head.
2. Ream cylinder head recess.
Reaming bore for service valve seat
Oversize [0.5 mm (0.020 inch)]:
Intake 35.500 - 35.516 mm (1.3976 - 1.3983 inch)
Exhaust 31.500 - 31.516 mm (1.2402 - 1.2408 inch)
Use the valve guide center for reaming to ensure valve seat will have the correct fit.

3. Heat cylinder head to 110 to 130°C (230 to 266°F).
4. Press fit valve seat until it seats on the bottom.
5. Cut or grind valve seat to the specified dimensions using a suitable tool. Refer to Engine; Specifications; Mechanical.
6. After cutting, lap valve seat with abrasive compound.

7. Check valve seating condition.
Seat face angle "a": 44°53'- 45°07'
Contacting width "W":
Intake 1.05 - 1.35 mm (0.0413 - 0.0531 inch)
Exhaust 1.25 - 1.55 mm (0.0492 - 0.0610 inch)

Use a depth gauge to measure the distance between the mounting surface of the cylinder head spring seat and the valve stem end. If the distance is shorter than the specified valve, repeat step 5 above to adjust it.
If it is longer, replace the valve seat with a new one.
Valve seat resurface limit: 42.74 - 43.26 mm (1.6827 - 1.7031 inch)

VALVE DIMENSIONS

Check dimensions of each valve. Refer to Engine; Specifications; Mechanical.
When valve head has been worn down to 0.5 mm (0.020 inch) in margin thickness, replace valve.
Grinding allowance for valve stem tip is 0.2 mm (0.008 inch) or less.

VALVE SPRING
Squareness

1. Measure dimension "S".
Out-of-square "S": Less than 2.1 mm (0.083 inch)
2. If it exceeds the limit, replace spring.

Pressure

Check valve spring pressure at specified spring height.
Pressure:
Standard 519 - 571 N (52.9 - 58.2 kg, 116.7 - 128.4 lbs.) at 27.0 mm (1.063 inch)
Limit More than 491.8 N (50.16 kg, 110.56 lbs.) at 27.0 mm (1.063 inch)
If it exceeds the limit, replace spring.

HYDRAULIC LASH ADJUSTER

1. Check contact and sliding surfaces for wear or score.

2. Check diameter of lash adjuster.
Outer diameter: 16.980 - 16.993 mm (0.6685 - 0.6690 inch)

3. Check lash adjuster guide hole diameter.
Inner diameter: 17.000 - 17.020 mm (0.6693 - 0.6701 inch)
Standard clearance between lash adjuster and adjuster guide hole: 0.007 - 0.040 mm (0.0003 - 0.0016 inch)

ROCKER ARM, SHIM AND ROCKER ARM GUIDE

Check contact and sliding surfaces of rocker arms, shims and rocker arm guides for wear or score.

Assembly

CAUTION:
^ When installing rocker arms, camshaft and oil seal, lubricate contacting surfaces with new engine oil.
^ When tightening cylinder head bolts, camshaft sprocket bolts and camshaft bracket bolts, lubricate bolt threads and seat surfaces with new engine oil.

1. Install valve component parts.

^ Install valves, noting their identification marks as indicated in the table.
^ Always use new valve oil seal.
^ Before installing valve oil seal, install valve spring seat.

^ Install valve spring (uneven pitch type) with its narrow pitched side (paint mark) toward cylinder head side.
^ After installing valve components, use plastic hammer to lightly tap valve stem tip to assure a proper fit.
2. Check hydraulic lash adjusters.

Fig. 35 Checking Hydraulic Lash Adjuster:

a. Push on the rocker arm above the hydraulic lash adjuster. If it moves 1 mm (0.04 inch) or more, there is air in the high pressure chamber of hydraulic lash adjuster.
Noise will be emitted from hydraulic lash adjuster if engine is started without bleeding air.

b. Remove hydraulic lash adjuster and dip in a container filled with new engine oil. While pushing plunger as shown in figure, lightly push check ball using a thin rod. Air is completely bled when plunger no longer moves.
Air cannot be bled from this type of lash adjuster by running engine.

3. Remove camshafts, rocker arms and shims. For future reference, identify each shim with the cylinder it was removed from. Since the shims are reusable, it may not be necessary to replace all of the existing shims.

4. Before attempting any measurement, make sure the valve, valve spring, collet, retainer and rocker arm guide are properly installed in the head.
^ Always replace rocker arm guide with a new one.

CAUTION: Install parts in their original positions.

5. Install the J38957-1 gauge plate into the tapped holes at the cam journals and secure it to the head using two of the hex bolts supplied with the kit. (The two remaining bolts are spares.)

6. Place the J38957-2 collar on the J38957-8 dial indicator. Make sure the dished side of the collar is facing "up" (toward the dial indicator). Secure the collar to the dial indicator by tightening the set screw in the collar.
7. Place the indicator and collar over #1 cylinder intake valve shim side. Slide the tip of the dial indicator through the access hole and place it on the end of the valve stem. While resting the dial indicator collar on the gauge plate, "zero" the dial indicator.

8. Move the dial indicator and collar to the adjacent hole in the gauge plate and place the tip of the indicator in the center of the rocker arm guide. Write down the dial indicator reading. This measured distance between the valve stem end and the contact surface of the rocker arm guide is the "T1" dimension.
9. Match the measured "To" dimension (in inches) to the available shim chart (in millimeters). (The "T1" dimension is equivalent to the thickness and size designation of the valve shim.) Select the closest size shim to the measured "T1" dimension. For example, if the measured "T1" dimension is 0.1152 inch, use a 2.925 mm (0.1152 inch) shim. Shims are available in 17 different thicknesses ranging from 2.800 mm (0.1102 inch) to 3.200 mm (0.1260 inch) and increase in increments of 0.025 mm (0.0010 inch).
10. Repeat this procedure on the remaining cylinders.

11. Install intake manifold with intake manifold collector as shown

12. Install exhaust manifold.
^ Tighten exhaust manifold bolts in numerical order.
Exhaust manifold: 37.8 - 48.1 Nm (3.8 - 4.9 kg-m, 28 - 35 ft. lbs.)

13. Install EGR volume control valve assembly.

14. Install EGR tube.
15. Install exhaust manifold cover.
16. Install water outlet.
a. Remove old liquid gasket from mating surface of water outlet.
^ Also remove old liquid gasket from mating surface of cylinder head.

b. Apply a continuous bead of liquid gasket to mating surface of water outlet.
^ Use Genuine RTV silicone sealant part No. 999MP-A7007 or equivalent.